Mr Martin, chief executive of GCHQ's National Cyber Security Centre (NCSC), said Britain had been hit by 188 high-level attacks, "many of which threatened national security" in the last three months.

There has been a step change in Russian aggression in cyber spaceCiaran Martin, GCHQ

He told The Sunday Times: "In the case of government departments, (it is) getting into the system to extract information on UK government policy on anything from energy to diplomacy to information on a particular sector."

Attempts by Russian and Chinese state-sponsored hackers on defence and foreign policy secrets are among the attacks being investigated by the NCSC, the newspaper said.

Mr Martin added: "Over the last two years there has been a step change in Russian aggression in cyber space.

"Part of that step change has been a series of attacks on political institutions, political parties, parliamentary organisations and that's all very well evidenced by our international partners and widely accepted."

Mr Hammond, a former defence and foreign secretary, said the NCSC had blocked 34,550 "potential attacks" on government departments and members of the public in the last six months – a rate of around 200 hacks a day.

"Beyond hacked kettles and fridges, 'internet of things' devices, such as driverless cars, can present alarmingly real security threats that could be incredibly dangerous if the right security isn't in place," he added.

Their comments come ahead of the Queen's official opening of the NCSC in London on Tuesday.